Networks are used to distribute information among computer systems. Typically packets or cells are transmitted and received over networks that connect the computer systems. With packets for instance, to determine the appropriate destination of each packet, processors such as microprocessors, central processing units (CPU's), and the like access header data stored in each packet to identify the appropriate destination. As the packets are transmitted and received the header data no longer needed is often removed. Alternatively, additional header data may be inserted into the packets to direct the packets to other appropriate destinations. Additionally, after adding or removing header data, some processors such as network processors insert data into each packet for later verifying that packet content has not been lost or erroneously added during transmission of the packet.